Mechanism for raising feed and other tables or platforms



Feb. 11,- 1930. J. l. NAsMlTH 4ET AL 1,746,712

`MECHANISM FOR RAISING FEED AND .OTHER TABLES OR PLATFORMS 2 Sheets-Sheet Filed 0G11. 23. 1928 ms N Febl1` 1930- l J. l. NAsMlTH Er Al. 1,746,712

MECHNISM FOR RAISING FEED AND OTHER TABLES OR PLATFORMS Patented Feb. 11, 1930 i UNITED STATES PATENT j OFFICE l y JOHN IRVING NASMITH, OF ELTHAM, LONDON, ANI)` CHRISTOPHER BRUNSWICK CHICKEN, OF IBEXLEY HEATH, ENGLAND, ASSIGNOl-S TO VICKERS-AR-MSTRONG LIMITED, OF WESTMINSTER, ENGLAND MECHANISM FOR RAISING FEED AND OTHER TABLES 0R PLATFORMS Application led October 273, 1928, Serial No. 314,436, and in Great Britain August 31, 1928.

This invention relates to mechanism for raising feed and other tables or platforms and has particular reference to mechanism for `raising the feed tables of sheet feeding ap- I, paratus of the type in which a pile of sheets or cards is supportedby the table, andthe latter is progressively raised as the pile diminishes due to the successivefeeding of the top sheets. In conjunction with sheet feeding apparatus of this typeV it has been proposed to support the feed table by levers operable on the lazy tongs7 principle from an operating member consisting of a toothed rack movable longitudinally in a horizontal d direction by worm gearing and connected to the lower end of one of the said levers. This arrangement possesses certain drawbacks since themechanical advantage is very adverse when the load is heaviest and the speed of the table as it rises, or the amount by `which the table rises with a unit movement of the operating member, varies considerably between the initial and inalpositions of the table. The object of the present invention is to overcome these drawbacks by controlling the amount by which the table rises when the operating member is actuated.`

According to the invention the table raising mechanism comprises an operating member adapted to impart vertical movement to the table through the medium of levers operable on the lazy tongs principle and means for modifying or changing the normal char acter of movement of thesaid levers so that a predetermined movement is imparted to the table. The lower ends of the levers are mounted so as to permit one toapproach the other as the angles between the levers are varied and the table israised. The moveinentpmodifying means may comprise an 1nclined prop or strut the lower end of which is movable along a stationary cam surface and the upper end -of which may be connected to one or both of the levers but is preferably connected to the central pivot of such levers.

The opera/ting member may comprise a rod or toothed rack movable longitudinally in a horizontal or substantiallyhorizontal path and having one end thereof connected tothe lower end of the said prop or strut. The cam surface is shaped so that the prop or strut operating in conjunction with the said levers is caused to impart a predetermined movement (which may be varied by varying the shape of the cam) to the table and by suitably forming this surface equal increments of movement of the operating member may produce equal or substantially equal incrementsof movement of the table.` In some cases the stationary cam surface may be substituted by a movable cam platepivotally mounted on the central pivot of the lazy tongs7 levers antico-operating with a stationary roller, said cam receiving its motion from the said operating member.

In order that the said invention may `beA 4' clearly understood and readily carried into effect, the same will nowbe described more fully with reference to the accompanying drawings, in which l Figure l is a side elevation of a table raisv feed table movable in a verticalV direction.

f, f1 are the levers operable on the lazy tongs principle, therebeing two sets of such levers disposed on opposite sides ofthe feed table. The lower end of the lever f is pivotally mounted in a fixed supportA g and the lower 1 end of the other lever f1 is pivotally connected by a pin t to a block c' which is slidably mounted on a horizontal bar y' supported at its ends in a pair of blocks c. The upper end of lever f is similarly connected by a pin to a block Z slidably mounted on a horizontal bar m supported from the lower surface of the feed table and the upper end of the lever f1 is pivotally connected to a lug ln, which is secured to or formed integral with the feed table. The levers on the opposite side of the feed table are arranged and mounted in a similar manner and the central pivot of one set of levers is connected to that of the other set by a. transverse shaft o.

p is the stationary cam surface made up of 'two tracks which are formed at the upper parts `of a pair of spaced vertically disposed plates g held in their appropriate relative positions by transverse bolts r. s is the inclined prop or strut which is interposed between the shaft o and the cam surface p and in order to facilitate its movement over the cam surface `the lower end of the prop is pivotally connected to a pin t which is provided with a pair of spaced rollers u, the spacing of the rollers corresponding with that of the plates q. The end of the operating member a is also secured to the pin t and it will be evident that when the operating member is moved to the left in Figure lthe rollers u will be caused to travel along the cam tracks and thus cause the upward movement of the transverse shaft 0 with the result that the angles between the levers f and )"1 will be varied and the feedtable d raised. In Figures 3 and 4 the operating member is indicated at a1. As in the previous arrangement the operating member is formed with teeth b1 to' enable it to be moved longitudinally by a pinion 01. Z1 is the feed table and f2, f are the levers operable on the lazy tongs principle, the lower end of the lever f2 being pivotally mounted in a fixed support g1 and the lower end of the other lever f being pivotally connected by a pin h1 to a block il which is slidably mounted on a horizontal bar jl supported at its ends in a pair of fixed blocks k1. The upper end of the lever f2 is similarly connected by a pin to a block i2 slidably mounted on a horizontal bar m1 supported from the lower surface of the feed table and the upper end of the lever f is pivotally connected to a lug n1 secured to or formed integral with the feed table. Another pair of lazy tongs levers are arranged and mounted in a similar manner on the opposite side of the feed table and the central pivot of one set of levers is connected to that of the other set by a transverse shaft 01. In this instance, instead of employing stationary cam tracks as in the arrangement shown in Figures 1 and 2, a movable cam plate g1 is pivotally mounted upon th'e transverse shaft 01 and connected at a2 to the operating member a1 the active surface of the pivoted cam plate g1 bearing against a stationary roller fv mounted on the frame of the machine. Movement of the said operating menn-y ber a1 will cause the pivoted cam to co-operate with the roller o and raise the feed table d as in the arrangement already described. In the examples shown, the cam tracks or the pivoted cam are shaped in such a manner that equal increments of movement of the operating member are caused to produce equal or substantially equal increments of movement, of the table so that the mechanical advantage of the arrangement is substantially constant and the movement of the table rendered more uniform.

What we claim and desire to secure by Letters Patent of the United States is z- 1. Mechanism for raising feed and other tables comprising table supporting levers operable on the lazy-tongs7 principle, an operating member and means for modifying the normal character of movement of the levers so that a predetermined movement is vimparted to the table.

2. Mechanism for raising feed and other tables comprising table supporting levers operable on the lazy-tongs principle, an operating member, and means associated with the levers for equalizing the upward increments of movement of the table resulting from equal increments of movement of the operating member.

3. Mechanism for raising feed and other tables comprising table supporting levers operable on the lazy-tongs principle, an operating member for varying the angles between the levers and means interposed between the 'levers and the operating member for controlling the amount by which Vthe table is moved upon actuation of the operating member.

fle. Mechanism for raising feed and other tables comprising table supporting levers operable on the lazy-tongs principle, an operating member movable in a horizontal path and means whereby equal increments of movement of the operating member produce equal increments of movement of thev table.

5. Mechanism for raising feed and other tables comprising table supporting levers operable on the lazy-tongs principle, a cam plate having its cam surface facing upwardly, an inclined prop having its upper end connected to one of the levers and its lower end movable over the cam surface and means for causing the lower end of the prop to move along the cam surface.

6. Mechanism for raising feed and other tables comprising pivotally connected table supporting levers operable on the lazytongs principle, a vertically disposed cam plate having a cam surface formed at the upper end thereof, an inclined prop having its upper end connected to the central pivot of the levers and its lower end resting on the cam surface and an operating member for causing the lower end of the prop to move along the cam surface.

Mechanism for 'raising feed andother tables comprising table supporting levers operable on the lazy-tongs principle and means for causing the lower ends of the le= vers to approach one another, the said means comprising a cam pla-te and an inclined prop having its upper end connected to one of the levers and its lower end movable along the cam plate.

JOHN IRVING NASMITH. CHRISTOPHER BRUNSWICK CHICKEN.A 

